This invention relates to superabrasive products and particularly to products having the form of a coated abrasive.
The term "superabrasive" is conventionally used to refer to materials with great hardness and toughness that can be used to abrade very hard materials without suffering significant polishing of the cutting edges or fracture of the abrasive particles. Superabrasives are typified by cubic boron nitride, ("CBN"), and diamond. Because they are able to abrade intractable materials such as glass, ceramics, marble, stone, and very hard metals, they are frequently held in metal bonds to ensure this quality is not compromised by bonds of inadequate strength for such purposes. The abrasive is sometimes electroplated to a substrate, perhaps through a mask to produce isolated islands of abrasive having either a single grain or a plurality of superabrasive crystals within each said island. However electroplating has disadvantages in the absence of adhesion between the bond and the abrasive particles. Said superabrasive grains can also be adhered to a substrate by means of brazing which greatly increases the retention of the grains with concomitant increase in abrading performance.
While superabrasives are significantly more expensive than conventional abrasives, their potential longevity and the precision and finish of the surface obtained on tough materials is sufficiently attractive to make their use a subject of continuing interest.
Another current interest in the field of coated abrasives is the use of engineered abrasives in which the abrading surface is provided by a plurality of composites with abrasive grits dispersed in a cured resin matrix. The shape and size of the composites can be engineered to provide any desired level of cutting and/or surface finish. Such products are exemplified by U.S. Pat. Nos. 5,014,468; 5,152,917; 5,833,724; 5,840,088 and 5,863,306.
The present invention lies at the confluence of these trends and provides a means to secure the advantages of superabrasives in the context of an engineered abrasive surface.